Update references to version 2.10.0

src/algs/slsqp/slsqp.c (src/algs/slsqp/slsqp.c): Fix the check for more
equality constraints than variables (introduced by PR #593 to fix #592)
so that vector constraints (mconstraints) are correctly counted: the
count to consider here is ptot (the total number of scalar equality
constraints), not p (the number of equality constraints that may be
vector constraints).

* slsqp: check p>n

Closes #592

* Update src/algs/slsqp/slsqp.c

---------

Co-authored-by: Steven G. Johnson <stevenj@mit.edu>

Closes #589

Closes #584

* C++: Allow disabling exceptions in opt::optimize.

Call opt.set_exceptions_enabled(false) before opt.optimize to avoid
throwing an exception. The caller is then responsible for checking the
returned result or opt.last_result(). The advantage is that, for the
SWIG-friendly overload, the returned best point (which can be quite good
in, e.g., the roundoff_limited case) is not lost (but then the caller
MUST check opt.last_result() to know whether anything has gone wrong).
The default is exceptions_enabled=true, so by default, nothing changes.

src/api/nlopt-in.hpp (opt::exceptions_enabled): New private member
variable.
(opt::opt (all overloads)): Initialize it (default it to true, copy it
in the copy constructor).
(opt::operator=): Copy it.
(opt::optimize): Only call mythrow if exceptions_enabled.
(get_exceptions_enabled): New public inline getter.
(set_exceptions_enabled): New public inline setter.

* Document set_exceptions_enabled and get_exceptions_enabled

doc/docs/NLopt_C-plus-plus_Reference.md,
doc/docs/NLopt_Guile_Reference.md,
doc/docs/NLopt_Python_Reference.md (Performing the optimization): Add
"by default" wording to the claim that `optimize()` throws an exception
for negative return codes. (The sentence already links to the
"Exceptions" section that has the details.)
(Exceptions): Document nlopt::opt::set_exceptions_enabled and
nlopt::opt::get_exceptions_enabled, and adapt the remainder of the
section to mention their impact where appropriate.

* Java: Document setExceptionsEnabled and getExceptionsEnabled

doc/docs/NLopt_Java_Reference.md (Performing the optimization): Add
"by default" wording to the claim that `optimize()` throws an exception
for negative return codes. (The sentence already links to the
"Exceptions" section that has the details.)
(Exceptions): Document nlopt.Opt.setExceptionsEnabled and
nlopt.Opt.getExceptionsEnabled, and adapt the remainder of the section
to mention their impact where appropriate.

* Testing: Add test for set_exceptions_enabled

test/t_java.java: Tests exception handling. This tests a test case known
to fail (t_bounded.cxx on LD_SLSQP) with set_exceptions_enabled set to
true if the argument is 1, false if the argument is 0, and verifies that
the exception is thrown resp. not thrown, as expected.

test/CMakeLists.txt: Add the C++ test t_except with the instances 1
(true = exceptions enabled) and 0 (false = exceptions disabled). Both
instances pass.

CMakeLists.txt: Add NLOPT_JAVA option. If set, check for C++, JNI, and
Java (>= 1.5, because of varargs and enums).

src/swig/nlopt-java.i: New SWIG input file (not standalone, but to be
included into nlopt.i). Contains the Java-specific declarations.

src/swig/nlopt.i: Add syntax highlighting declaration for KatePart-based
editors. Call the module NLopt instead of nlopt for SWIGJAVA, because in
Java, this is the name of the globals class (not the package, which is
set separately on the SWIG command line), so it should be in CamelCase.
Instantiate vector<double> as DoubleVector instead of nlopt_doublevector
for SWIGJAVA, because everything is in an nlopt package in Java, so the
nlopt_ part is redundant, and because it should be in CamelCase. Ignore
nlopt_get_initial_step because at least for Java, SWIG wants to generate
a binding for it, using SWIGTYPE_p_* types that cannot be practically
used. (It is in-place just like nlopt::opt::get_initial_step, which is
already ignored.) Rename nlopt::opt::get_initial_step_ to the
lowerCamelCase getInitialStep instead of get_initial_step. For SWIGJAVA,
%include nlopt-java.i.

src/swig/CMakeLists.txt: Set UseSWIG_MODULE_VERSION to 2 so that UseSWIG
cleans up old generated source files before running SWIG, useful for
Java. (In particular, it prevents obsolete .java files from old .i file
versions, which might not even compile anymore, from being included in
the Java compilation and the JAR.) Update the path handling for the
Python and Guile bindings accordingly. If JNI, Java, and SWIG were
found, generate the Java binding with SWIG, and compile the JNI library
with the C++ compiler and the Java JAR with the Java compiler. For the
Guile binding, set and unset CMAKE_SWIG_FLAGS instead of using
set_source_files_properties on nlopt.i, because nlopt.i is shared for
all bindings, so setting the property on the source file does not help
preventing breaking other target language bindings (such as Java). Also
replace the deprecated swig_link_libraries with target_link_libraries.

src/swig/glob_java.cmake: New helper script whose main purpose is to
invoke the CMake file(GLOB ...) command at the correct stage of the
build process, after the SWIG run, not when CMake is run on the main
CMakeLists.txt, because the latter happens before anything at all is
built. The script is invoked through cmake -P by an add_custom_command
in CMakeLists.txt, whose dependencies order it to the correct spot of
the build. This is the only portable way to automatically determine
which *.java files SWIG has generated from the *.i files. The result
is written to java_sources.txt, which is dynamically read by the add_jar
command thanks to the @ indirection. In addition, it also does a
replacement in DoubleVector.java, changing double[] initialElements to
double... initialElements (introduced in Java 1.5), which needs to
happen at the same stage of the build, so that initial elements can be
passed directly to new DoubleVector without extra new double[]{
boilerplate.

test/t_java.java: New test. Java port of t_tutorial.cxx/t_python.py.

test/CMakeLists.txt: If JNI, Java >= 1.8, and SWIG were found, run the
t_java test program with the algorithms 23 (MMA), 24 (COBYLA), 30
(augmented Lagrangian), and 39 (SLSQP). All 4 tests pass. (Java < 1.8
should be supported by the binding itself, but not by the test.) Update
the PYINSTALLCHECK_ENVIRONMENT settings for the src/swig/CMakeLists.txt
changes, so that the Python tests keep passing. Update the
GUILE_LOAD_PATH settings for the src/swig/CMakeLists.txt changes, so
that the Guile tests keep passing.

This code is mostly unrelated to the old unmaintained nlopt4j binding
(https://github.com/dibyendumajumdar/nlopt4j), which used handwritten
JNI code. Instead, it reuses the existing SWIG binding infrastructure,
adding Java as a supported language to that. Only the code in the
func_java and mfunc_java wrappers is loosely inspired by the nlopt4j
code. The rest of the code in this binding relies mostly on SWIG
features and uses very little handwritten JNI code, so nlopt4j was not
useful as a reference for it. This binding is also
backwards-incompatible with nlopt4j due to differing naming conventions.

Note that this binding maps the C++ class and method names identically
to Java. As a result, it does not use idiomatic Java case conventions,
but uses snake_case for both class and method names instead of the usual
UpperCamelCase for class names and lowerCamelCase for method names in
Java. The C++ namespace nlopt is mapped to the Java package nlopt.

doc/docs/NLopt_Java_Reference.md: New file, based on
NLopt_Python_Reference.md and NLopt_Guile_Reference.md, adapted to the
Java syntax.

doc/docs/NLopt_Tutorial.md: Add example in Java.

doc/docs/index.md: Mention Java, linking to NLopt_Java_Reference.md.

README.md: Add Java. (The link will become valid after the commit makes
it into master and the documentation on readthedocs is regenerated.)

Including iostream means introducing the static (global) constructors
and destructors for std::cin, std::cerr, and std::cout. That extra
init and fini code is undesirable when those streams are not actually
used.

Closes #581

Closes #579

Closes #575

Closes #528

Closes #379